One example of a prior heat exchanger used, for example, in a room heating convector apparatus includes, for example, a pipe through which hot water flows, plural fins on the pipe, and a blower for blowing air across the pipe and fins so that the air is heated during such passage. Another example of a conventional heat exchanger is the radiator apparatus of a motor vehicle, and still other examples are domestic and commercial furnaces, boilers, hot water heaters, etc.
The various prior heat exchanger are inefficient in a number of respects. Typically a liquid flowing through a pipeline of the heat exchanger generally experiences laminar flow in which there is minimal boundary layer movement relative to the central stream area, and the slow motion at the boundary layer area tends to create a thermal insulating effect. Thus, heat transfer to the material of the pipeline is impeded by the boundary layer insulation and the laminar flow with relatively higher velocity center-stream conditions further reduce the transfer of heat energy to the heat transfer medium of the pipeline. Moreover, to increase the outside surface area of the heat exchanger, which is typically designed to have air or other gas blown thereacross, fins are welded or otherwise secured to the outside surface of the pipeline. The connections of the fins to the outside surfaces of the pipeline frequently impede the conduction of heat between the pipeline material and the major portion of the fin material. Additionally, at such junctions, there frequently is a build-up of heat, which further impedes the conduction of heat thereat.
Other disadvantages with prior art heat exchangers are their large size, equipment cost, and operation cost. A disadvantage of present automotive radiators is the large size and weight thereof. These all contribute negatively to principles of conservation of energy, natural resources, capital, space, etc.
There are, of course, three types of heat transfer, namely conduction, convection and radiation. Conduction is the most efficient and most heat exchangers employ both conduction and convection. However, conduction with respect to fluid in the heat exchanger is impeded and made inefficient due to the boundary layer insulation effect mentioned above.